2012

Pulse Ox Screening for Congenital Heart Disease

January 26, 2012

Newborn screening has dramatically reduced mortality and morbidity for several conditions, but not for congenital heart disease (CHD), which has been responsible for more deaths in the first year of life than any other birth defect. But that outcome may be changing soon, said pediatric resident Erica Elzey at a recent Hopkins Children’s grand rounds, noting that the American Academy of Pediatrics (AAP) – following recommendations from the Department of Health & Human Services (HHS) – has proposed a screening test for CHD using the simple, non-invasive test pulse oximetry, which measures oxygen levels in blood.

“Adding this screening for newborns,” Elzey said, “grew out of a lot of evidence in the literature showing that pulse oximetry can help enhance detection of critical congenital heart disease over current methods, including prenatal ultrasound and physical exam” (Pediatrics 2011;128(5):e1271-2).

Elzey explained that the screening test, recommended for well-baby and intermediate-care nurseries, targets structural heart defects generally associated with hypoxia that require medical interventions like surgery or catheterization in the first year of life. Those conditions include hypoplastic left heart syndrome, pulmonary atresia, tetralogy of Fallot, total anomalous pulmonary venous return, transposition of the great arteries, tricuspid atresia, and truncus arteriosus.

“The goal is to have earlier detection of the congenital heart diseases that require early intervention,” Elzey said.

The screening, Elzey added, should be done after the first 24 hours of life because of variations in oxygen saturation in the first few hours of life. The pulse oximeter, cleared for use in newborns by the Food and Drug Administration, should be placed on the right hand and one foot. Under an algorithm developed by the AAP, American Heart Association (AHA), the American College of Cardiology Foundation and HHS, the screen is abnormal if oxygen saturation is less than 90 percent in either location. The screen is normal if oxygen saturation is greater than 95 percent in the hand or foot and there is a less than 3 percent difference between hand and foot. Hourly rescreens are recommended in infants with saturations between 90-95 percent, or if the difference is greater than 3 percent. If after two repeat screens, criteria for negative screen have not been met, screening is considered positive. A positive screen should prompt a complete evaluation for causes of hypoxemia.

“If you can’t find a specific explanation for the hypoxemia,” Elzey said, “then the patient should have an echocardiogram, which should be read by a pediatric cardiologist.”

Elzey added that research is needed on screening special populations, like those living in high altitudes, and to evaluate telemedicine strategies for nurseries without on-site echocardiography. Central to the effectiveness of screening, she added, will be the development of a national technical assistance center to coordinate implementation and evaluation of newborn screening for critical congestive heart diseases.